Jungiusstr. 11, Hörsaal AP
SFB 668 - Kolloquium
Prof. Dr. Frithjof Nolting (Uni Basel / PSI):
A close look at magnetic multilayers and nanomagnets with X-ray microscopy
Exploring the world of reduced dimensions in solid state physics is a challenging and rewarding research area. A powerful tool to investigate the magnetic properties of nanoscale systems is X-ray photoemission electron microscopy (XPEEM) employing X-ray magnetic linear dichroism (XMLD) and X-ray magnetic circular dichroism (XMCD) . Using recent results I will explain the technique and its possibilities.
One example is the study of magnetic multilayers where we search for ways to control the magnetization of a medium by means other than magnetic fields. Recently, it has been demonstrated that laser-excitation of a bulk antiferromagnet may result in subpicosecond modification of magnetic anisotropy followed by 90-degree reorientation of antiferromagnetic spins within few picosecond. Here we present experimental results on the laser control of spins in ferromagnet-antiferromagnet heterostructure Co/SmFeO3. Another example is the study of the magnetic properties and scaling laws of nanoparticles. Using PEEM, we discovered a size-dependent transition from a single domain state to a non-collinear spin structure in isotropic nanoparticles with sizes ranging from 25 down to 5 nm . Further examples will be about patterned magnetic nanostructures  and how the magnetization of ferromagnetic systems can be manipulated by ultrashort laser pulses.
 F. Nolting, A. Scholl, J. Stöhr, J.W. Seo, J. Fompeyrine, H. Siegwart, J.-P. Locquet, S. Anders, J. Lüning, E.E. Fullerton, M.F. Toney, M.R. Scheinfein, and H.A. Padmore, Nature 405, 767 (2000).
 Fraile Rodríguez, A. Kleibert, J. Bansmann, A. Voitkans, L. J. Heyderman, and F. Nolting, Phys. Rev. Lett. 104, 127201 (2010).
 E. Mengotti, L. J. Heyderman, A. Fraile Rodríguez, F. Nolting, R.V. Hügli, and H. B. Braun, Nature Physics Nature Physics 7, 68 (2011).